Re: [PATCH v13 11/27] drm/i915/hdmi: Add YCBCR444 handling for sink formats

Ville Syrjälä
2026-04-13T19:04:29Z

On Mon, Apr 13, 2026 at 09:58:22PM +0300, Ville Syrjälä wrote:
> On Mon, Apr 13, 2026 at 12:07:25PM +0200, Nicolas Frattaroli wrote:
> > In anticipation of userspace being able to explicitly select supported
> > sink formats, add handling of the YCBCR444 sink format. The AUTO path
> > does not choose this format, but with explicit format selection added to
> > the driver, it becomes a possibility.
> >
> > Check for YCBCR444 support on the sink in both sink_bpc_possible, and
> > sink_format_valid.
> >
> > Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> > ---
> > drivers/gpu/drm/i915/display/intel_hdmi.c | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
> > index 874076a29da4..5ab5b5f85cde 100644
> > --- a/drivers/gpu/drm/i915/display/intel_hdmi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
> > @@ -1966,6 +1966,8 @@ static bool intel_hdmi_sink_bpc_possible(struct drm_connector *_connector,
> >
> > if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR420)
> > return hdmi->y420_dc_modes & DRM_EDID_YCBCR420_DC_36;
> > + else if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR444)
> > + return info->edid_hdmi_ycbcr444_dc_modes & DRM_EDID_HDMI_DC_36;
> > else
> > return info->edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_36;
> > case 10:
> > @@ -1974,6 +1976,8 @@ static bool intel_hdmi_sink_bpc_possible(struct drm_connector *_connector,
> >
> > if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR420)
> > return hdmi->y420_dc_modes & DRM_EDID_YCBCR420_DC_30;
> > + else if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR444)
> > + return info->edid_hdmi_ycbcr444_dc_modes & DRM_EDID_HDMI_DC_30;
> > else
> > return info->edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_30;
> > case 8:
> > @@ -2038,6 +2042,11 @@ intel_hdmi_sink_format_valid(struct intel_connector *connector,
> >
> > return MODE_OK;
> > case INTEL_OUTPUT_FORMAT_RGB:
> > + return MODE_OK;
> > + case INTEL_OUTPUT_FORMAT_YCBCR444:
>
> We'll also want the !has_hdmi_sink check here like for 4:2:0.
>
> And I think we also want something to mirror the ycbcr_420_allowed
> flag. I guess you could just make it something like:
>
> intel_hdmi_ycbcr_444_allowed(display)
> {
> return DISPLAY_VER(display) >= 5 && !HAS_GMCH(display);

Actually the display version check is redundant there.
!HAS_GMCH alone is sufficient.

> }
>
> That can also be reused when setting up the allowed property values.
>
> > + if (!(info->color_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444)))
> > + return MODE_BAD;
> > +
> > return MODE_OK;
> > default:
> > MISSING_CASE(sink_format);
> >
> > --
> > 2.53.0
>
> --
> Ville Syrjälä
> Intel

--
Ville Syrjälä
Intel